A laser has many components. Because a laser is a precision instrument, many of these components must be of high precision. One such component is the optical resonator structure. The optical resonator structure has a cavity in which the active lasing medium is excited to produce the beam of coherent radiation. At one end of the optical resonator cavity is a first highly polished mirror, which is nearly one hundred percent (100%) reflective; a second highly polished mirror is at the other end, which is less reflective than the first mirror and permits some of the radiation to be transmitted therethrough. Coherent radiation generated within the optical resonator cavity is reflected from the first mirror to the second mirror until sufficient amount of energy of coherent radiation is generated and is transmitted through the second mirror.
Because the optical resonator structure must be aligned such that photons of radiation reflected from one mirror is incident on the other mirror, the structure must be extremely precisely aligned. Any misalignment can cause the laser to produce a reduced output or even to fail to generate a beam of laser radiation. The optical resonator structure must be precisely aligned, even when it is subjected to variation in alignment and position due to variations in the ambient temperature. In addition, heat generated within the optical resonator cavity caused by the excitation of the lasing medium can cause the optical resonator structure to become misaligned or mispositioned.
In the prior art, it is known to use a stablizing fluid, such as water or oil, which is heated to a fixed temperature and passed into the optical resonator structure to maintain the structure at a fixed temperature. This, however, requires the use of a fluid which is different from the lasing medium, thereby necessitating another set of plumbing fixtures and the like. In addition, the temperature of the stablizing medium is generally maintained by a simple thermostatic heater. To our knowledge, there has never been a laser using a temperature stablizing lasing medium whose temperature is actively controlled. By active control, it is meant that the temperature is sensed, is compared to a fixed reference, and in response to the comparison, the temperature of the fluid is changed, all of which is done in a closed loop feedback control configuration.
Another component of a laser is the power-supply. The power supply generally comprises a plurality of lines (usually three) connected to a three-phase power source. These plurality of lines are connected to a set of primary coils (also usually three), which are wound about a transformer. A plurality of secondary coils (also usually three) are also wound about the transformer. The transformer increases the voltage of the secondary coil from the primary coils. In the prior art, to control the mode of operation of the laser from continuous to pulsing, usually a control device, such as a vacuum tube, is used. Since a vacuum tube runs on DC voltage, and since the power supplied to the primary coils is AC in nature, the vacuum tube is placed in the circuit after the secondary coils. Since the secondary coils receive an increased voltage from the transformer (usually on the order of tens of thousands of volts), the vacuum tube must be suitable for such high voltage application. Necessarily, these tubes are expensive.
To our knowledge, in the prior art, there has not been any system to control the power output of a laser in response to the desired level of power output. In addition, to our knowledge, there is no laser system having an active pressure control loop to control the pressure of the gas lasing medium.
In September of 1982 at the International Machine Tool Show in Chicago, Ill., a system was disclosed wherein a fixed laser generated a fixed beam of coherent radiation. A robot having an articulated arm moved a work piece in and out of the beam of coherent radiation to effectuate various cutting and scribing actions onto the work piece as a result of the relative movement of the fixed beam of coherent radiation and the movable work piece. In the medical area, a laser generating a beam of coherent radiation has been delivered to a desired location by passing the beam of coherent radiation through an articulated arm wherein the movement of the articulated arm moves the beam. However, to our knowledge, in the prior art, there has not been any industrial system to deliver a beam of coherent radiation to a desired location by a mechanical assembly which comprises a plurality of coupled structural members in one of which the laser is located. The movement of the assembly moves the laser and the beam to deliver the beam to the desired location. Finally, to our knowledge, there is no prior art relating to a distributive lasing system wherein a centralized pump and power supply delivers the electrical power and the active gas lasing medium to a plurality of remotely located optical resonator structures to activate the lasing action.